I tried this, doesn't work.
I have another question...
is there a limit that is set somewhere on the system, that does not allow the creation of more user quotas?
e.g. a global limit per inodes, blocks etc?
I have noticed that after I add some users , from one point and on it cannot set quotas to the users....

edquota: Can't write quota for user31 on /dev/vzfs: No such process

also, the blocks and inodes for the newly added users appear 0 0 in edquota

note: the users that are created, are created manually with the useradd command, not via new cpanel accounts.

I would be wondering if there are some file system problems on the VPS you're on since quotaing should be working before you get near the VPS. You may need to backup and have it restored if problems persist and you don't find a solution. It's difficult to know when you're not using a "real" file system.